window: Fix use-after-free in menu button handler

Commit d2fbb3870c introduced a use-after-free
error in the case where we destroy the menu.

clients/window.c

@@ -3363,11 +3363,10 @@ menu_button_handler(struct widget *widget,
 			   menu->current, menu->window->parent->user_data);
 		input_ungrab(input);
 		menu_destroy(menu);
-	}
+	} else if (state == WL_POINTER_BUTTON_STATE_RELEASED) {
-
-	if (state == WL_POINTER_BUTTON_STATE_RELEASED)
 		menu->release_count++;
 	}
+}
 
 static void
 menu_redraw_handler(struct widget *widget, void *data)